Electron Configuration

• What should you be able to do by the end of the video?


  Work out electron configuration of elements
• What is an atomic orbital?

  A region around a nucleus for electrons
• How many electrons can an atomic orbital hold?

  Up to two electrons
• What are the types of orbitals mentioned?

  s, p, d, and f orbitals
• What is a subshell?

  All orbitals of the same type in a shell
• What happens to the energy of subshells as you move away from the nucleus?

  Energy increases
• What is the first rule for filling orbitals?

  Fill lowest energy orbitals first
• How many electrons can occupy the same orbital?

  Two electrons with opposite spins
• What is the third rule for filling orbitals with the same energy?

  Put electrons into individual orbitals first
• How do you represent an electron's spin?

  Using an arrow
• What is the electron configuration of hydrogen?

  1s$^1$
• How many electrons does helium have?

  Two electrons
• What is the electron configuration of helium?

  1s$^2$
• How many electrons does lithium have?

  Three electrons
• What is the electron configuration of lithium?

  1s$^2$ 2s$^1$
• How many electrons does nitrogen have?

  Seven electrons
• What is the electron configuration of nitrogen?

  1s$^2$ 2s$^2$ 2p$^3$
• What does the electron configuration show?

  Only the subshells, not individual orbitals
• What are the three rules for filling atomic orbitals?

  1. Fill lowest energy orbitals first
  2. Maximum of two electrons per orbital with opposite spins
  3. Electrons in same energy orbitals occupy individual orbitals before pairing
• What is the significance of the electron configuration in chemistry?

  • Describes the distribution of electrons in an atom
  • Helps predict chemical behavior and bonding
  • Essential for understanding periodic trends
• What are the exceptions to the rules of electron configuration?

  • Some elements have unexpected electron configurations
  • These exceptions arise due to stability considerations
  • Important for understanding transition metals and lanthanides
• What is the focus of the second video in the series?

  Working out electron configuration of atoms
• What determines the order in which orbitals are filled?

  Orbitals with the lowest energy are filled first
• How many electrons can occupy the same orbital?

  Up to two electrons with opposite spins
• Why do we fill individual orbitals before pairing electrons in orbitals of the same energy?

  Electrons in the same orbital repel each other
• What is the electron configuration of oxygen?

  1s2 2s2 2p4
• What does the electron configuration represent?

  It shows sub shells but not individual orbitals
• How many orbitals does the d subshell contain?

  Five orbitals
• Which subshell is filled before the 3d subshell?

  The 4s subshell
• How do you fill the orbitals for iron with 26 electrons?

  Fill 1s, 2s, 2p, 3s, 3p, 4s, then 3d
• What is the electron configuration of iron?

  1s2 2s2 2p6 3s2 3p6 3d6 4s2
• In what order is the electron configuration written?

  In the order of electron shells
• How do you determine the electron configuration for vanadium with 23 electrons?

  Fill 1s, 2s, 2p, 3s, 3p, 4s, then 3d
• What is the electron configuration of vanadium?

  1s2 2s2 2p6 3s2 3p6 3d3 4s2
• What are the exceptions to the electron configuration rules?

  Chromium and copper
• How many electrons does chromium have?

  24 electrons
• How many electrons does copper have?

  29 electrons
• What is the actual electron configuration of chromium?

  4s1 3d5
• What is the actual electron configuration of copper?

  4s1 3d10
• Why is the 3d subshell more stable when half or completely full?

  It minimizes electron repulsion